The present invention relates generally to a device for supporting firearms, such as rifles and shotguns, during test firing, and more particularly to an improved portable device for absorbing firearm recoil during test firing.
Hunters and target shooters often need to test fire their guns at a fixed target from a secure, stable or "benched" position for various purposes, such as evaluating ammunition loads and adjusting sights or scopes (known as "sighting-in"). The goal of such bench firing is to eliminate external variables, such as the technique of the shooter, which may adversely effect the trajectory of a fired projectile.
To facilitate repeated firings from a benched position, a mechanical device is often used to support the firearm. Such devices typically support the firearm at one or more points to aid in achieving the desired stability upon firing. These devices range from simple sand bags to complex bench-mountable recoil absorbing devices.
During test firing, the shooter often prefers to grip the firearm in a fairly normal manner, that is, to the extent permitted by the supporting apparatus. However, after a series of test firings, the shooter's shoulder may become quite sore from absorbing the recoil of the firearm held in an unnatural position dictated by the supporting device. This is particularly true when test firing high power rifles or magnum ammunition loads. Thus, it is desirable to reduce or eliminate the recoil to allow the shooter to fire as many rounds as necessary without suffering any resulting soreness.
During test firing for sighting-in a firearm or scope, the shooter must view down the sight path from a normal firing position. However many known supporting devices are so bulky and cumbersome that the shooter cannot attain nor maintain a clear, comfortable sighting position.
Some known supporting devices progressively absorb the firearm recoil force after firing as the firearm travels from an initial rest position prior to firing to a rearmost recoil position. However, no control is provided for returning the firearm from the rearmost recoil position forward to the initial rest position. Such uncontrolled return motion results in harsh reciprocation and jarring impacts of the device and firearm as the apparatus reaches a resting point. Such severe mechanical impacts may damage the components of a scope mounted to the test firearm.
Additional drawbacks of known supporting devices include time-consuming, complex means of securing the device to a bench, often requiring special tools or fasteners. Furthermore, some devices require perfectly level or specially contoured surfaces upon which they must be mounted. Such requirements seriously detract from the usefulness of the device, particularly for shooters using a variety of shooting ranges with varying facilities.
One such known device for supporting a rifle during accuracy testing is disclosed in U.S. Pat. No. 3,805,608 to Schmidt et al. A frame has two parallel shafts slidably mounted thereon at each end by fore and rear sets of bearings to move longitudinally relative to the frame. To secure a firearm, a butt clamp and a fore clamp are each rigidly mounted on opposing ends of the two parallel shafts adjacent the bearings, with the butt clamp outboard of the rear bearings and the fore clamp inboard of the fore bearings. Each shaft has a concentric spring retaining collar rigidly mounted thereon between the butt and fore clamps, and toward the butt clamp end of each shaft. Each shaft has a spring concentrically mounted thereon between the rear bearings and the spring retaining collar.
The Schmidt et al. device suffers from several disadvantages. For example, the firearm recoil energy induces relative motion between the shafts and frame which is absorbed by the two springs. After arresting the rearward recoil motion, the device fails to provide any means for controlling the forward acceleration of the shafts as the springs release the stored recoil energy. The forward motion is only stopped when the butt clamp abruptly impacts with the rear bearings which may damage the device, the firearm or any scope mounted thereto. The butt clamp also includes a rearwardly protruding bolt which prevents a shooter from shouldering and properly sighting the firearm in a conventional manner. Furthermore, the frame requires the use of bolts and a special mounting surface having corresponding bolt holes therethrough for mounting the device.
Another known apparatus for supporting a rifle during test firings is shown in U.S. Pat. No. 4,333,385 to Culver. Two parallel rails are rigidly mounted at each end by abutments to a base. A carriage, having fore and rear sliders with bearings mounted therein, is slidably mounted by the sliders to the rails between the abutments. A butt clamp and a fore clamp are mounted generally above the respective rear and fore sliders to support a firearm. A foamed block plastic cushion surrounds each end of the rails in a space between each slider and the adjacent abutment to absorb the recoil energy.
The Culver device also suffers several disadvantages. For example, the device is not durable, as the foam block cushions will wear and degrade over time, such as by taking a permanent compressed set, inhibiting the recoil absorbing function. Furthermore, the butt clamp includes a rearwardly extending toggle and an angle adjustment knob, which, in addition to the generally bulky form of the apparatus, prevents a shooter from shouldering the firearm during test firing. The base also includes a downwardly projecting flange which extends over a front edge of a mounting surface to prevent rearward travel of the apparatus during firing. This requires the mounting surface to have a proper width for convenient use of the flange along with bolt holes to mount the apparatus thereto.
A pistol supporting device is shown in U.S. Pat. No. 2,731,829 to Wigington et al. This device has two parallel rails rigidly mounted at each end to a base by fore and aft transverse bracket bars. The device also includes a pistol-supporting carriage slidably mounted to the rails and biased toward the fore bracket bar by two recoil absorbing springs, each mounted to one of the rails. Adjustment collars may be inserted between the springs and aft bracket bar, or between the fore bracket bar and carriage, to very the spring tension.
The Wigington et al. device also has a variety of disadvantages. For example, the pistol stocks must be removed prior to mounting the pistol. This is excessively time consuming and prohibits holding the firearm in a normal fashion. Furthermore, no damping is provided for returning the carriage from a rearmost position after firing back to the initial position adjacent the fore bracket bar. Also the base must disadvantageously be bolted to a mounting surface having pre-drilled holes therethrough.
Other known devices include electro-pneumatic recoil absorbers for quality control testing by firearm manufacturers, gun-mounted recoil buffers for machine guns, and recoil mechanisms for tank-mounted U.S. Pat. Nos. 2,599,265, 2,831,404 and 2,966,829.
Thus, a need exists for an improved firearm recoil absorbing device which is not susceptible to the above limitations and disadvantages.